Syringobulbia in Patients with Chiari Malformation Type I: A Systematic Review

Successful treatment of unilateral facial nerve palsy in a pediatric patient with syringobulbia and Chiari malformation type I: illustrative case

BACKGROUND

Unlike syringomyelia, syringobulbia is not commonly observed in pediatric patients with Chiari malformation type I (CMI). Previous series have reported the incidence of syringobulbia as between 3% and 4% in these patients. Presentation is typically chronic, with the slow onset of neurological symptoms and cranial nerve (CN) palsies resulting from lower brainstem involvement. The authors report the first case of a pediatric patient with simultaneous CMI, syringobulbia, and unilateral CN VII palsy.

OBSERVATIONS

A 7-year-old male presented with right facial weakness in addition to headaches, ataxia, urinary incontinence, and falls. Magnetic resonance imaging revealed CMI with a syrinx of the cervicothoracic spine and syringobulbia. Posterior fossa decompression with duraplasty was performed without complications, and the patient was discharged home on postoperation day 5. At the 3-week follow-up, the patient's neurological deficits had largely subsided. At the 3-month follow-up, his CN VII palsy and syringobulbia had completely resolved.

LESSONS

Pediatric CMI patients with syringomyelia are at risk for developing syringobulbia and brainstem deficits, including unilateral facial palsy. However, craniocervical decompression can prove successful in treating such deficits.

Respiratory arrest after posterior fossa decompression in patients with Chiari malformations: An overview

Background

Chiari malformation type 1 (CM1) is a structural abnormality in the skull and cerebellum, causing cerebellar tonsils to shift downward. Decompression of the posterior fossa is a common surgical method to relieve symptoms and prevent neurological deterioration. After posterior fossa decompression (PFD), individuals with CM1 were more likely to have respiratory arrest. Here, we present, for the first time, a comprehensive overview of the potential risk factors and causes of respiratory arrest following PFD.

Methods

A review of the literature highlighting the risk factors for postoperative respiratory arrest in CM1 patients was conducted in the databases of PubMed, Medline, and Google Scholar.

Results

Patients with syringomyelia and CM1 are at increased risk for respiratory arrest due to a number of factors, including impaired respiratory mechanics, central respiratory center dysfunction from edema or ischemia, intraoperative brain stem ischemia, and delayed gastric emptying from autonomic dysfunction. Occipitalization of the first cervical vertebra, basilar impression, and fusion of C2-C3 are all risk factors for respiratory arrest.

Conclusion

Implications for CM1 patient care and prospects for further investigation of postoperative respiratory arrest's causes and risk factors were discussed.

Chiari Malformation Type 1 and Syringomyelia: Why Do Patients Claim for International Guidelines? Commentary on the 2021 Chiari and Syringomyelia Consensus Document

The diagnosis of Chiari malformation type 1 (CM1) and Syringomyelia (Syr) has become increasingly common during the past few years. Contemporarily, the body of literature on these topics is growing, although randomized controlled studies on significant case series to drive guidelines are missing in the pediatric and adult populations. As a result of the different opinions about surgical indications and techniques raised by CM1-Syr, an increasing number of well-informed but disoriented patients is emerging. To bridge this gap, an International Consensus Conference on CM1-Syr held in Milan in November 2019 aimed to find a consensus among international experts, to suggest some recommendations that, in the near future, could lead to guidelines. Here, we comment on the most relevant recommendations about the definition, diagnosis, surgical management, failures and re-intervention, and outcome. We also focus on some "wrong" indications or techniques that, although widely disapproved by the experts, and negatively experienced by many patients, are still largely in use.

Neurophysiological Correlates in Patients with Syringomyelia and Chiari Malformation: The Cortico-Diaphragmatic Involvement

Purpose. Brainstem syndromes have frequently been reported in Chiari syndrome and in syringobulbia; previous studies have shown that determining the central motor conduction time (CMCT) along the circuit of the phrenic nerve makes the assessment of the voluntary control of the respiratory pathway possible. In our study, we evaluated the transcranial magnetic stimulation (TMS) of the phrenic nerve in patients affected by Chiari syndrome and/or syringomyelia (Syr) with the aim of identifying subclinical neurophysiological alterations. Methods. One hundred patients (75 females; average age: 51 ± 13.08 SD; range: 18–76) affected by Chiari syndrome and/or Syr without dyspnea were selected. The magnetic stimulation of the second motor neuron correlating with the phrenic nerve was performed using cervical magnetic stimulation (C5-MEP); the cortical MEP after magnetic stimulation (Cz-MEP) was recorded by magnetic stimulation of the motor cortex (areas corresponding to the diaphragm). The CMCT was calculated. The differences between the patients and controls were calculated (Student’s t test). Results. In 13% of the patients, the Cz-MEP were absent bilaterally, and the CMCT was not evaluable. In all these cases, bulbar/cervical Syr was present at MRI; in 10 of them, this was associated with CM1. A bilateral response was obtained in all the other patients (87%), and the CMCTs were normal. All the patients with alterations/absence of Cz-MEP presented bulbar/cervical Syr at MRI. The C5-MEP latency was prolonged or absent in 48%; of these, 84% presented bulbar/cervical Syr associated with CM1 at MRI. The C5-MEP latency values were significantly higher in the group of patients. Conclusions. Neurophysiological alterations of the diaphragmatic pathway were recorded in a group of Chiari syndrome and, particularly, in bulbar/cervical Syr. Future studies with larger cohorts of patients are needed to further assess the specific role of the TMS of the phrenic nerve in CM/Syr patients.

Diagnosis and treatment of Chiari malformation and syringomyelia in adults: international consensus document

BACKGROUND

Syringomyelia and Chiari malformation are classified as rare diseases on Orphanet, but international guidelines on diagnostic criteria and case definition are missing.

AIM OF THE STUDY

to reach a consensus among international experts on controversial issues in diagnosis and treatment of Chiari 1 malformation and syringomyelia in adults.

METHODS

A multidisciplinary panel of the Chiari and Syringomyelia Consortium (4 neurosurgeons, 2 neurologists, 1 neuroradiologist, 1 pediatric neurologist) appointed an international Jury of experts to elaborate a consensus document. After an evidence-based review and further discussions, 63 draft statements grouped in 4 domains (definition and classification/planning/surgery/isolated syringomyelia) were formulated. A Jury of 32 experts in the field of diagnosis and treatment of Chiari and syringomyelia and patient representatives were invited to take part in a three-round Delphi process. The Jury received a structured questionnaire containing the 63 statements, each to be voted on a 4-point Likert-type scale and commented. Statements with agreement <75% were revised and entered round 2. Round 3 was face-to-face, during the Chiari Consensus Conference (Milan, November 2019).

RESULTS

Thirty-one out of 32 Jury members (6 neurologists, 4 neuroradiologists, 19 neurosurgeons, and 2 patient association representatives) participated in the consensus. After round 2, a consensus was reached on 57/63 statements (90.5%). The six difficult statements were revised and voted in round 3, and the whole set of statements was further discussed and approved.

CONCLUSIONS

The consensus document consists of 63 statements which benefited from expert discussion and fine-tuning, serving clinicians and researchers following adults with Chiari and syringomyelia.

Diagnosis and treatment of Chiari malformation type 1 in children: the International Consensus Document

BACKGROUND

Chiari malformation type 1 (CM1) is a rare condition where agreed classification and treatment are still missing. The goal of this study is to achieve a consensus on the diagnosis and treatment of CM1 in children.

METHODS

A multidisciplinary panel formulated 57 provisional statements based on a review of the literature. Thirty-four international experts (IE) participated in a Delphi study by independently rating each statement on a 4-point Likert scale ("strongly disagree," "disagree," "agree," "strongly agree"). Statements that were endorsed ("agree" or "strongly agree") by < 75% of raters were re-formulated, or new statements were added, and another Delphi round followed (up to a maximum of three).

RESULTS

Thirty-five IE were contacted and 34 agreed to participate. A consensus was reached on 30/57 statements (52.6%) after round 1. Three statements were added, and one removed. After round 2, agreement was reached on 56/59 statements (94.9%). Finally, after round 3, which took place during the 2019 Chiari Consensus Conference (Milan, Italy), agreement was reached on 58/59 statements (98.3%) about four main sections (Definition and Classification, Planning, Surgery, Isolated Syringomyelia). Only one statement did not gain a consensus, which is the "definition of radiological failure 24 month post-surgery."

CONCLUSIONS

The consensus document consists of 58 statements (24 on diagnosis, 34 on treatment), serving clinicians and researchers following children with CM1. There is a clear need for establishing an international network and registry and to promote collaborative studies to increase the evidence base and optimize the long-term care of this patient population.

Jacqueline du Pré and her alternative diagnosis

JacquelineduPré (26 January 1945-19 October 1987) is one of the greatest cellists in the 20th century. Her musical career was terminated at age 28, allegedly due to multiple sclerosis (MS). MS is an immune-mediated demyelinating disease of the central nervous system with axonal involvement, characterized by the dissemination in time and space of the lesions (plaques). Diverse neurological symptoms may occur in MS, and a variety of symptoms relentlessly accumulated in her case after the diagnosis in 1973, which is concordant with primary progressive rather than relapsing-remitting form of MS. No radiological confirmation was however possible in her days and the diagnosis should be reconsidered, because her symptoms had some unusual features in MS. First, her principal symptoms, aside from transient visual and urological problems noticed earlier, began in the upper and lower limbs, often only in the upper limbs, then followed by the involvement of lower cranial nerves, and by the cognitive decline with changes in character. Hence the pattern of progression was ascending from the cervical spinal cord to the brainstem and to the cerebrum, which is not the pattern of dissemination in space typical of MS. Her clinical status appeared steroid-dependent temporarily in the early stage of the disease, which is also unusual in MS and some different etiology deserves consideration. We suppose that Uhthoff phenomenon, i.e. worsening of symptoms by the elevation of body temperature, may have been negative contrary to the previous interpretation, and if we are correct the absence of this sign does not support the demyelinating pathophysiology of her disease. Now that there is no objective medical information sufficiently disclosed, another scenario may be hypothesized, although MS is still a likely possibility. We discuss that syringomyelia/syringobulbia associated with Chiari malformation type I and obstructive hydrocephalus can be an alternative diagnosis.